If you have no rights to the article, then you can't just take it. Writers use copyscape to make sure their work isn't haunting other sites, and I've heard a lot about cease and desist orders involving infringement. There is something called the DMCA that is a big old monster waiting to pounce on ppl who violate copyright, and I think the penalties are pretty nasty. Copyright happens the minute a writer writes something down, so I really suggest you get permission prior to putting someone's work on your site.